1. Field of the Invention
The present invention relates to a liquid crystal display device, and more particularly, to a liquid crystal display device provided with a sensing electrode for sensing a touch of a user.
2. Discussion of the Related Art
A liquid crystal display device is widely used in various fields of notebook computers, monitors, spacecraft, aircraft, and etc. owing to advantages of low power consumption based on a low driving voltage and portability.
The liquid crystal display device includes a lower substrate, an upper substrate, and a liquid crystal layer formed between the lower and upper substrates. In the liquid crystal display device, an alignment state of liquid crystal molecules in the liquid crystal layer is controlled based on whether or not an electric field is applied thereto, and light transmittance is controlled according to the alignment state of liquid crystal molecules, whereby images are displayed thereon.
It is general that a mouse or key board is used as an input means of the liquid crystal display device. However, a touch screen, which can allow a user to directly input information using a finger or pen, is mainly applied to a navigation system, a portable terminal and electric home appliances.
Hereinafter, a related art liquid crystal display device provided with a touch screen will be described with reference to the accompanying drawings.
FIG. 1 is a cross-sectional view illustrating the related art liquid crystal display device.
As shown in FIG. 1, the related art liquid crystal display device includes a liquid crystal panel 10 and a touch screen 20.
The liquid crystal panel 10 displays images, and includes a lower substrate 12, an upper substrate 14, and a liquid crystal layer 16 formed between these substrates 12 and 14.
The touch screen 20 is formed on the liquid crystal panel 10 to sense a touch of a user, and includes a touch substrate 22, a first sensing electrode 24 formed below the touch substrate 22, and a second sensing electrode 26 formed on the touch substrate 22.
The first sensing electrode 24 is arranged below the touch substrate 22 in a horizontal direction, and the second sensing electrode 26 is arranged on the touch substrate 22 in a vertical direction. Accordingly, if the user touches a predetermined position, capacitance between the first sensing electrode 24 and the second sensing electrode 26 is varied at the touched position. As a result, the position where capacitance is varied is sensed, whereby the touch position of the user can be sensed.
However, in the aforementioned related art liquid crystal display device, since the touch screen 20 is separately formed on the liquid crystal panel 20, the overall thickness of the liquid crystal display device is increased by the touch screen 20. For this reason, problems occur in that manufacturing process steps are complicated and the manufacturing cost is increased.